Pkogess of treating concentrates



W. G. SWART AND B..G. KLUGH.

PROCESS OF TRE ATING'CONCINTRATES. APPLIC-ATIOP} FILED NOV.-17, F9]?-1,308 ,41 1 Patented May 13, 1919.

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"WALTER. G. SWART, F DULUTH, MINNESOTA, AND BETHUNE Gr. K'LTJ'GH, 0FANNISTUN,

ALABAMA. i

PROCESS Oil TREATING CONCENTRATES.

Specification of Letters Patent.

Patented an is, rare.

Application filed November 17, 1917. Serial No. 202,455.

To all whom it may concern:

Be it known that we, WALTER G. SWART,

- a citizen of the United States, residing at ti l Duluth, in the countyof St. Louis and State of Minnesota, and Bernese Gr. KLUGH, a citizen ofthe United States, residing at Anniston, in the county of Calhoun andState of Alabama, have invented certain new and useful Improvements inProcesses of Treating Concentrates, of which the folloiving is aspecification.

This invention relates to improvements in processes of treatingmetalliferous ores, and has for its especial object the preparing offinely divided iron-bearing material, for example, such as concentratesof ores; ores naturally existing as very fine sand, earth, dust, orclay, or artificial ores; or by-products carrying iron values, forsintering or other agglomerating processes, and also natural orartificial ores requiring desulfurization, dehydration, or eliminationof any volatile constituents by volatilization of such constituents.

Finely divided or clayey iron-bearing materials, require some form ofagglomeration before they can be e iciently treated in blast furnaces.Agglomei ation by such blast roasting processes as the Heberlein, thelDwightv and Lloyd, and the Grecnawalt, for instance, requires, first,that the finely divided or clayey iron-bearing material. to beagglomerated shall be intimately and thoroughly mixed with solid fuel,preferably carbonaceous and finely divided, prior to its delivery to theblast roasting or sintcring apparatus; and, second, that such mixture ofsolid fuel and finely divided or clayey iron-bearing material bedelivered to such sintering apparatus containing a definite percentageof water or other iiuid, which so tempers it, or brings it to sucha'state of plasticity, tl' it contains the largest possible volume orpercentage of voids, which is desirable for best sintering practice.

it happens that much of the finely divided and clayey iron-bearingmaterial occurring naturally and the concentrates made artificiallycontain approximately the right amount'of moisture to give them theproper degree of plasticity, or can be brought easily to this condition,but it also happens that this condition or degree of plasticity is thatat which it is most difficult to secure the necessary intimate mixtureof the material or concentrate with the solid fuel. The gummy, stickynature of the mass is such as to interfere seriously with the successfuloperation of any mixing device now in use, requiring a heavy excess ofpower, giving much trouble from breakage of machine parts, necessitatingfrequent stopping of machines for cleaning out caked and packed masses,and delivering a product imperfectly mixed..-

In the case of the pug mill or blade type of mixer, theplastic materialbuilds up into hard cakes on all surfaces adjacent to the peripheralpath of the blades, thus causing a braking action on the blades withenormously increased power consumption and wear on the blades. In thectise of the drum or cylindrical type of mixer the gummy material buildsup on all surfaces with which it comes in contact, forming cakes ormasses difficult to dislodge, causing an excess power consumption,reducing the mixing area and volume of the apparatus, and giving poormixing. lit intervals the mixers must be stopped and cleaned or allmixing stops. Such finely divided iron-bearing materials as finemagnetiteconcentrates, now being eX- tensively produced, and oresnaturally plastic, such those Cuban ores known as Ma yari ores, areespecially productive of difiiculty and expense as just described.

By our invention we propose to eliminate the mixing devices asabovedescribed with theirattendant diiiiculties and expense.

i Vhcn finely divided oreis concentrated on tables, or in magnetic andother separators, the concentrates arc ci'lstomarily delivered from theconcentrating machines in a semi-fluid condition, due to the ex )8 ofWater contained therein. This excess of water must be removed beforesii'itering, and this removal may be effected in several ways, butfiltering machines of thc Oliver or Portland type ofler a desirablemethod.

in our process the finely divided fuel, which if necessary has beenpreviously crushed or ground, while either dry or wet, in suitablemachines such as ball mills, is introduccd'into the fluid mass ofconcentrates and thoroughly mixed thercwith by any suitable means, suchas a ccn ifugal pump, while the concentrates are still fluid; and tlexcess water is then removed by any suitable apparatus, such as arevolving filter, which delivers a plastic mass with fuel lilvli alreadyintimately mixed therewith, and in the best physical condition forsintering, without further mixing.

In the case of a sticky, gummy, or clayey ore occurring naturally, likethe Mayari Cuban ores already mentioned, we vary our process only byfirst adding sufficient water to the natural ore to bring it to asemi-fluid condition, then adding the finely divided fuel, as before,then thoroughly agitating and mixing the semi-fluid mass and filteringsame to the desired degree of plasticity. It has heretofore been foundimpossible to get a suitable mixture of fuel with this kind of ore toallow good sintering except at a prohibitive cost.

Certain (natural) ores and by-products (natural or artificial) containsulfur, combined water, or other volatile constituents, to an amountwhich renders them undesirable, or even totally unfit, for blast furnaceuse. When such ores occur massive they do not require agglomeration forthe purpose of keeping fines out of the blast furnace, but for theequally necessary purpose of removing the objectionable elementsmentioned. It is therefore necessary to crush such ores and sinter them,which sintering not only eliminates the fines, but at the same timeremoves these objectionable elements. Such procedure is now beingfollowed commer cially at several plants. The practice is to grind theore dry, add the necessary fuel, moisten to sintering consistency in themixer, then sinter the mass. Wet grinding is preferable, but not used,because an excess of water niust be added which would haveto besubsequently removed by drying, leaving the same sort of plastic mass asdescribed above, with which it is difficult to mix the necessary fuel.

Under the invention described herein, such ores may be ground Wet, havethe neces sary fuel added and mixed While the mass is still fluid, thenfiltered and sintered, as already described.

The fuel may be added to such ore previous to, or simultaneous with, orsubsequent to, the grinding of the ore, the mixed ore and fuel beingthen filtered and sintered.

Iron-bearing ore and other products are sometimes leached for theremoval of copper, zinc, or other substances, either in a natural stateor subsequent to roasting. Such leached n'iaterial is usually plasticand difficult to mix with fuel for subsequent sin tering. By our method,Water is added until the mass is fluid. Fuel is then added and easilymixed, the resulting mixture being fil tered and sintered, as hereindescribed.

As a further feature of this invention, we contemplate the use of peat,which to our knowledge has not heretofore been used as a fuel insintering or otherwise agglomerating ores. Peat usually occurs naturallyin such form that it must be maceraieu and dried before being used asfuel. It is not uncommon for it to be taken from the bogs carrying towater, most of which it is difficult and expensive to remove. in ourinvention we introduce the peat into the semi-fluid mass of concentratesor ore, without necessarily drying the peat, then agitate and mix thesemi-fluid mass of ore or concentrates and peat, and then filter thelluid mass, the result being a plastic mass containing' the necessaryfuel intimately mixed, ready for sintering, just as though finelydivided coal or coke, or other solid fuel, had been used.

Peat often occurs in swamps in a naturally semi-fluid condition. Ourinvention also covers the inverted procedure of int reducing the finelydivided iron-bearing materials into the fluid or pulpy peat, and thensul jecting the mixture to a filtering or dewatering operation,substantially as decribed, before agglomeration.

It is evident that in the ease of fuels other than peat, also, it makesno difference in the final result whether the ore is added to the fuelor the fuel to the ore, either or both being in the same liquid pulpycondition, or in the dry state.

To illustrate one method of carrying out our process, we have shown oneform of apparatus in the accompanying drawing. in which- A designates acrushed ore bin or hopper from which the finely crushed ore is deliveredto a concentrator indicated by B, the embodiment shown being of the typeknown as the Davis type, in which the ore is magnetically separated andat the same time conveyed to the upper end of the concentrator, where itis discharged in the form of a pulp or fluid mass into the launder C.Located above the latter is a bin D, in which is located the fuel in thedesired condition, such as peat, comminuted or ground to de siredcondition, a feed roller D being locat-ed beneath the open end thereofto deliver the fuel in desired proportion to the launder G, as indicatedby dotted lines. A valve D may be utilized to control the amount of fueldelivered. This fuel, together with the fluid pulp, floi '5 through themedium of the launder O, and (l, to a centrifugal pump E, where the fueland fluid ore particles are thoroughly mixed and commingled anddelivered through the conduit E to a filtering machine, generallyindicated by the letter F, and shown as of the Oliver or Portland type,the excess moisture being pumped out by the filtering machine in amanner well known to those skilled in the art, and the de-wateredmixture of ore and fuel is carried over on the lip or chute F to thefeeding hopper G which is located above the endless belt ll of asintering apparatus, for

example, generally indicated by the letter H. A slide valve G may beused to regulate the delivery oi the mixture to the sintering belt H Theapparatus for shite-ring shown here is of the Dwight and Lloyd type,although as in the case of the apparatus diagrammatically illustrated inthe drawing, we do not Wish to be restricted to any specific type orform of apparatus in the carrying out of this process, H indicates thesuction hex oi the sintering apparatus through the medium of whichcombustion carried through the mixture after ignition thereof and duringthe passage of the ex haust box H It will be apparent that, by theaddition of the fuel in the manner and at the time described, a thoroughhomogeneity of the mixture is obtained With a minimum of labor andexpense by utilizing a necessary step in the handling of theconcentrates.

It Will be obvious that While the carrying out of our process in theabove-descril'ied apparatus delivers the connninuted ore in a pulpy orfluid condition so as to flow readily, it is possible that we may treatline or plastic ores by reducing them to a fluid or pulpy conditionprevious to the mixture of the fuel therewith.

Further modifications and changes in our process as described arepossible and contemplated, and 'WG do not Wish to be restricted to theherein-described process save as defined in the appended claims.

What We claim is:

1. A. process of the class described conr prising the steps of mixingfuel and metallit'erous particles with Water to obtain a fluid mixture,then removing the excess water content, and then agglomerating themixture.

A. process of the class described cornrising the steps of mixing fuelwith metal.- liferous particles in a fluid state,-then moving the excessWater content, and then agglomerating the mixture.

A process oi the class described, consisting in first mixingmetalliterous particles of desired size with Water or the like, to

a state of fluidity, then adding fuel, next mixing said fuel and fluid,then removing" superfluous Water content, and finally gloinerating saidmixture.

l. A. process of the class described, con-- sisting in first mixingnietalliterous particles of the desired size with Water or the like to astate of fluidity, then adding peat thereto, next mixing said peat and1netallifero'us tluhr, then removing; superfluous water content fromsaid mixture, and finally agglonierating the same.

lln. testimony whereof, we have subscribed J. Kerr, ill l E,

Nicr-rotts ti ll

